Such cassettes are housings for coiling and protecting optical fibers, and often also for protecting connections or "splices" between the coiled optical fibers. Such cassettes are used for connecting various optical cables together, or for connecting an optical cable to optical jumpers. Each cassette is assigned to two fibers to be connected together, or preferably to several fibers to be respectively connected to several other fibers.
In general, a plurality of cassettes are assigned to handling all the fibers of one or more optical cables to be connected to one or more other optical cables or jumpers inside a splice box. The cassettes are stacked together to form an assembly so as to take up less space inside the splice box, and they are hinge mounted so that each of them can be accessed, in particular for maintenance purposes.
Document FR-A- 2,646,928 describes such an assembly of cassettes inside a splice box for optical fibers. In that document, the assembly of cassettes is mounted at the end of a support plate on which the ends of the cables to be interconnected are fixed. The support plate has side flanges to delimit a protected space in which to transfer the fibers to the assembly of cassettes, surplus lengths being left on the fibers at the ends of the cables.
In that assembly, the cassettes are stacked such that they are slightly offset from one another, and are hinged about individual axes that are similarly offset from one another. To that end, each of the cassettes carries a pair of side arms that swing about a pair of hinge axes on the side flanges of the support plate. Each cassette has a limited possible rotary stroke through which to rotate relative to the plane of the support plate, so that the cassette can be put into the open position transversely to the support plate. Temporary snap-fastening means are provided at the coupling between each pair of arms and the corresponding pair of hinge axes to limit said rotary stroke, and to define an open position.
Such dispositions for assembling and opening the cassettes are relatively complex, are difficult to implement, and are fragile. They require the assembly and the cassettes making up the assembly to be held on the flanges of a channel-section support. With such dispositions, it is relatively difficult to open the cassettes, because they are mounted on long hinged arms. Although the dispositions are organized to limit excessive stresses on the fibers and excessive curvature thereof, the lack of stability of the cassettes when they are being opened prevents the fibers from being properly held under the required conditions.